UNIVERSITY  OF  CALIFORNIA  PUBLICATIONS 

COLLEGE  OF  AGRICULTURE 

AGRICULTURAL  EXPERIMENT  STATION 

BERKELEY,- CALIFORNIA 


FIRE  PROTECTION  FOR  GRAIN  FIELDS 

WITH  SPECIAL  REFERENCE  TO 

FIRE  PROTECTIVE  APPLIANCES 
FOR  GRAIN-HARVESTING  MACHINERY 

BY 
WOODBRIDGE  METCALF 


A  thousand  acre  grain   fire. 

BULLETIN  No.  295 

May,  1918 


UNIVERSITY  OF  CALIFORNIA   PRESS 
BERKELEY 
1918 


Benjamin  Ide  Wheeler,  President  of  the  University. 

EXPERIMENT  STATION  STAFF 

heads  of  divisions 

Thomas  Forsyth  Hunt,  Director. 
Edward  J.  Wickson,  Horticulture  (Emeritus). 

Herbert  J.  Webber,  Director  Citrus  Experiment  Station ;  Plant  Breeding. 
Hubert  E.  Van  Norman,  Vice-Director;  Dairy  Management. 
William  A.  Setchell,  Botany. 
Myer  E.  Jaffa,  Nutrition. 
Charles  W.  Woodworth,  Entomology. 
Ralph  E.  Smith,  Plant  Pathology. 
J.  Eliot  Coit,  Citriculture. 
John  W.  Gilmore,  Agronomy. 
Charles  F.  Shaw,  Soil  Technology. 
John  W.  Gregg,  Landscape  Gardening  and  Floriculture. 
Frederic  T.  Bioletti,  Viticulture  and  Enology. 
Warren  T.  Clarke,  Agricultural  Extension. 
John  S.  Burd,  Agricultural  Chemistry. 
Charles  B.  Lipman,  Soil  Chemistry  and  Bacteriology. 
JClarence  M.  Haring,  Veterinary  Science  and  Bacteriology. 
Ernest  B.  Babcock,  Genetics. 
Gordon  H.  True,  Animal  Husbandry. 
James  T.  Barrett,  Plant  Pathology. 
Fritz  W.  Woll,  Animal  Nutrition. 
Walter  Mulford,  Forestry. 
W.  P.  Kelley,  Agricultural  Chemistry. 
H.  J.  Quayle,  Entomology. 
J.  B.  Davidson,  Agricultural  Engineering. 
Elwood  Mead,  Rural  Institutions. 
H.   S.  Reed,  Plant  Physiology. 
W.  L.  Howard,  Pomology. 
fFRANK  Adams,  Irrigation  Investigations. 
C.  L.  Roadhouse,  Dairy  Industry. 
O.  J.  Kern,  Agricultural  Education. 
John  E.  Dougherty,  Poultry  Husbandry. 
S.  S.  Rogers,  Olericulture. 
R.  S.  Vaile,  Orchard  Management. 
J.  G.  Moodey,  Assistant  to  the  Director. 
Mrs.  D.  L.  Bunnell,  Librarian. 

DIVISION  OF  FORESTRY 

Walter  Mulford  Charles  H.  Shattuck 

JDavid  T.  Mason  JDonald  Bruce 

Woodbridge  Metcalf 


$  In  military  service. 

t  In  co-operation  with  office  of  Public  Roads  and  Rural  Engineering,   U.   S. 
Department  of  Agriculture. 


FIRE   PROTECTIVE  APPLIANCES  FOR 
GRAIN-HARVESTING  MACHINERY 


By  WOODBRIDGB  METCALB 


California's  grain  crop  for  1918  has  assumed  an  importance  in  the 
present  emergency  far  greater  than  even  the  large  figures  suggest. 
These  show  that  cereal  crops  occupy  nearly  two  million  acres  of  land, 
or  approximately  30  per  cent  of  the  total  improved  acreage  in  the 
state.  Their  estimated  value  is  about  a  hundred  million  dollars.  Fig- 
ures, however,  do  not  suggest  the  proper  basis  for  valuation  of  this 
crop.  It  can  best  be  interpreted  in  terms  of  food  for  a  world  which 
needs  it  as  never  before.  Because  of  world  shortage  someone  is 
dependent  upon  every  bushel  of  grain  which  can  be  grown  and  har- 
vested. The  loss  of  even  a  small  quantity  means  that  someone  who 
is  deprived  of  it  will  have  to  go  hungry.  The  farmers  have  responded 
splendidly  to  the  call  by  putting  in  what  promises  to  be  the  largest 
crop  of  grain  raised  in  many  years.  This,  however,  is  not  enough. 
They  must  take  all  precautions  possible  to  prevent  losses  of  all  kinds, 
in  order  that  the  maximum  amount  may  be  delivered  and  put  to 
effective  use. 

In  the  past  fires  have  caused  very  serious  losses  to  the  grain  crop. 
So  serious  in  fact  have  these  been  that  in  spite  of  insurance  rates 
which  are  twice  as  high  as  those  in  "Washington  and  Oregon,  many 
fire  insurance  companies  have  considered  refusing  to  take  grain  risks 
until  conditions  show  improvement,  because  of  the  excessively  high 
loss  ratio.  Tf  their  estimate  of  loss  of  grain  in  California  amounting 
to  $250,000  a  year  for  the  past  few  years  is  translated  into  present 
values,  loss  of  a  similar  amount  of  grain  this  year  will  involve  a 
damage  over  twice  as  great.  At  50c  per  man  per  day  this  loss  would 
feed  10,000  of  our  boys  in  France  for  over  three  months,  and  if  only 
the  cereal  ration  is  considered  the  grain  thus  destroyed  would  supply 
this  number  of  men  for  nearly  three  years.  It  is,  therefore,  evident 
that  each  one  of  us  should  consider  it  a  patriotic  duty  to  adopt  such 
necessary  precautionary  measures  as  will  cut  this  loss  down  to  the 
absolute  minimum. 


352 


UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 


CAUSES    OF    FIRES 

It  has  often  been  said  that  four  out  of  every  five  fires  are  prevent- 
able, and  grain  fires  seem  to  be  no  exception  to  this  rule.  In  an 
attempt  to  discover  the  cause  of  these  fires  every  insurance  company 
doing  business  in  the  state  was  asked  for  data  on  their  losses  during 
the  past  three  years.  Replies  were  received  from  twelve  companies, 
reporting  on  a  total  of  260  fires  as  follows: 

Causes  of  Grain  Fires  in  California,  1915-1917 

No.  Per  cent 

Unknown   79  30.3 

Harvesting   machinery    78  30.0 

Eailway   28  10.7 

Miscellaneous    27  10.4 

Carelessness 21  8.1 

Smoking    20  7.7 

Incendiary 7  2.8 

260  100.0 


Fig-  2.— A  centrifugal  air  clarifier.  Air  enters  through  pipe  (c),  dirt  is 
dropped  and  collects  in  Mason  jar  (b),  clean  air  goes  to  carburetor  through  pipe 
A,  all  joints  of  which  should  always  be  kept  tight. 


FIRE  PROTECTION   FOR  GRAIN   FIELDS  353 

The  average  loss  per  fire  paid  was  found  to  be  $1515,  and  even 
when  one  very  large  loss  from  Imperial  County  is  disregarded,  the 
average  loss  is  well  over  $1000.  This,  of  course,  represents  the  amount 
paid  by  the  companies,  which  probably  is  not  over  75  per  cent  of  the 
value  of  materials  actually  destroyed.  It  seems,  therefore,  reasonable 
to  assume  that  if  the  average  fire  causes  a  loss  of  from  $1000  to  $1500, 
the  grain  man  is  certainly  warranted  in  expending  an  amount  at  least 
equal  to  6  per  cent  of  the  probable  damage  in  order  to  prevent  that 
fire  or  extinguish  it  quickly  if  it  starts. 

A  study  of  the  above  table  shows  that  grain  harvesting  machinery 
is  responsible  for  30  per  cent  of  the  fires,  being  by  far  the  most  im- 
portant known  cause.  The  other  causes  are  being  attacked  in  the 
most  effective  way  possible,  and  it  is  believed  that  by  education  of 
the  public  to  the  dangers  involved,  most  of  the  fires  in  the  "miscel- 
laneous," "carelessness"  and  "smoking"  classes  can  be  eliminated. 
The  railways  are  cooperating  in  an  effort  to  cut  down  preventable 
fires  along  their  rights-of-way. 

The  incendiary  must  be  watched  and  brought  swiftly  to  justice. 
The  following  rules  were  followed  last  year  in  Washington  with  good 
results:  "Forbid  strangers  access  to  any  part  of  your  premises  with- 
out proper  credentials,  no  matter  what  the  pretext.  Employ  no  one 
in  any  kind  of  service  whom  you  do  not  know  to  be  reliable  and  above 
suspicion.  Report  to  proper  officials  anyone  found  lurking  about 
your  premises.  Do  everything  which  suggests  additional  safety 
against  loss  or  damage  from  known  causes  and  all  unknown  causes 
which  clever  or  unscrupulous  enemy  sympathizers,  spies,  or  the 
ordinary  cranks,  stimulated  by  unusual  conditions,  are  liable  to  think 
of  or  devise." 

SAFEGUARDING    HARVESTING    MACHINERY 

Fires  set  by  harvesting  machinery  are  the  result  of  several  well- 
defined  causes,  all  of  which  can  be  largely  eliminated  by  the  adoption 
of  proper  precautionary  measures.  These  causes  in  their  relative 
order  of  importance  are  as  follows : 

1.  Hot  carbon  from  the  exhaust  of  tractor  or  auxiliary  engines. 

2.  Hot  boxes  in  any  of  the  moving  parts. 

3.  Ignition  of  straw  or  chaff  in  contact  with  exhaust  pipes  and 
manifolds. 

4.  Ignition  or  explosion  of  dusty  or  smutty  grain  by  static  elec- 
tricity sparks. 

5.  Sparks  caused  by  gravel,  matches,  or  foreign  matter  getting 
into  the  separator. 


354  UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 


CAEBON 

Carbon  results  from  imperfect  combustion  of  fuel,  the  residue 
from  the  lubricating  oil,  and  from  dust  drawn  into  the  cylinders  with 
the  air.  It  collects  there,  and  is  expelled  in  flakes  or  chunks  through 
the  exhaust  in  an  incandescent  state  and  sets  a  majority  of  the  fires 
attributed  to  harvesting  machinery.  To  control  these  sparks  effect- 
ually is  to  prevent  probably  75  per  cent  of  the  machinery-caused  fires 
in  grain. 

AIE  CLAEIFIEES 

Chemical  analysis  of  carbon  has  shown  43  per  cent  of  it  to  consist 
of  field  dirt  and  dust.  This  not  only  adds  to  the  fire  menace,  but 
scores  out  the  inside  of  the  cylinders  to  a  very  appreciable  extent.  So 
true  is  this  in  dusty  weather  that  Professor  Davidson  states  it  to  be 
a  mechanical  crime  to  operate  a  tractor  under  dusty  conditions  with- 
out a  clarifier. 


Fig.  3. — The  vacuum  bag  air  clarifier.  Air  enters  through  pipe  and  against 
baffle  plate  (A),  is  strained  through  canton  flannel  bag  (B),  which  catches  all 
dirt  and  passes  out  the  top  through  pipe  (C)   to  the  carburetor. 


FIRF,  PROTECTION   FOR  GRAIN   FIELDS 


356 


Clarifiers  are  of  two  kinds,  the  centrifugal  and  the  vacuum  bag. 
The  air  is  either  rotated  or  passed  through  a  canton  flannel  bag,  so 
that  all  solid  matter  which  it  may  contain  is  removed  before  it  enters 
the  carburetor.  Clarifiers  are  now  installed  on  all  tractor  and  har- 
vester engines  and  should  be  considered  an  absolute  necessity  during 
harvest  time.  The  pipe  leading  from  the  clarifier  to  the  carburetor 
should  be  carefully  inspected  each  day  to  see  that  the  joints  are  tight. 
If  there  are  leaks,  much  dirt-laden  air  will  be  taken  in  and  the 
efficiency  of  the  device  impaired. 

SPARK  ARRESTERS 

In  spite  of  the  use  of  a  clarifier  there  will  always  be  some  carbon 
coming  from  the  exhaust  which  must  be  caught  and  held  in  some 
effective   manner    if   we    are   to    eliminate    fires.      All   of   the    larger 


Fig.  4. — The  old  conical  type  spark  arrester  is  entirely  ineffective  in  stopping 
sparks.  Gases  are  concentrated  at  the  apex  which  has  often  burned  out  or  blown 
off  while  red  hot.     The  use  of  this  arrester  in  harvest  fields  should  be  discontinued. 

machines  have  been  equipped  with  so-called  spark  arresters  in  tin' 
past,  but  the  types  in  use  up  to  this  time  have  given  very  poor  pro- 
tection for  the  following  reasons  : 

1.  They  are  built  on  the  wrong  principle,  as  in  the  conical  type 
which  concentrates  the  gases  at  the  apex  instead  of  dispersing  them. 
In  several  cases  bad  fires  have  been  caused  by  the  apex  of  the  cone 
blowing  off  into  the  grain  while  red  hot. 


356  UNIVERSITY    OP    CALIFORNIA — EXPERIMENT    STATION 

2.  The  mesh  of  the  screen  is  too  coarse,  allowing  sparks  to  pene- 
trate and  so  set  fires. 

3.  In  many  cases  carbon  and  rust  have  collected  in  flakes  on  the 
outside  of  the  arrester  to  be  blown  off  when  a  particularly  strong 
explosion  comes. 

4.  Under  certain  conditions,  particularly  with  an  excess  of  fuel  or 
lubricating  oil,  the  exhaust  gases  become  ignited  on  the  outside  of  the 
screen  and  will  flame  like  a  torch  for  several  minutes.  This  condition 
is  particularly  dangerous  in  windy  weather. 


Pig.  5. — An  assembled  Harris  spark  arrester  and  its  component  parts.  It  is 
simple,  easy  to  keep  in  repair  and  if  kept  clean  has  given  good  protection  from 
sparks  where  used  on  auxiliary  engines.  If  larger  area  of  screen  is  desired  the 
separators  and  bolts  can  be  lengthened.  The  Yuba  tractors  will  hereafter  be 
equipped  with  arresters  of  this  design. 

In  an  endeavor  to  have  these  things  corrected  at  the  source  in  so 
far  as  possible,  the  tractor  and  harvester  manufacturers  of  the  state 
were  visited  and  the  importance  of  the  matter  placed  before  them. 
Excellent  cooperation  was  secured  from  all  of  the  companies,  who  at 
once  set  out  to  devise  better  protective  devices  for  their  particular 
machines.  New  machines  are  being  equipped  with  these  and  owners 
can  secure  the  new  equipment  for  old  machinery  from  the  respective 
companies  or  their  regular  local  agents. 

The  Best  Gas  Traction  Company,  San  Leandro,  has  adopted  a  new 
double  screen  arrester  with  heavy  top  and  bottom  castings  instead  of 
the  old  conical  type. 

The  Yuba  Manufacturing  Company,  Benicia,  and  the  Harris  Man- 
ufacturing Company,  Stockton,  have  adopted  arresters  of  simple  and 
almost  identical  design,  consisting  of  heavy  top  and  bottom  castings 
held  together  with  three  bolts  and  grooved  on  the  edges.  Double 
thickness  of  window  screen  is  tightened  into  these  grooves  by  means 
of  a  double  strand  of  baling  wire.  The  screen  if  worn  can  be  replaced 
in  a  few  minutes,  the  only  requirements  being  the  screen,  baling  wire, 
and  a  pair  of  pliers.     These  will  give  reasonably  good  protection  if 


FIRE   PROTECTION   FOR   GRAIN   FIELDS  35"3 

the  screen  is  whole.  They  should  be  brushed  off  and  the  carbon 
shaken  out  of  the  inside  at  least  once  a  day.  Under  very  dangerous 
conditions  it  may  be  necessary  to  cover  them  with  a  larger  screened 
cylinder  of  the  Hahn  type. 

The  Holt  Company  of  Stockton  has  developed  a  centrifugal  type 
of  arrester  built  on  a  principle  similar  to  that  of  the  clarifier.  The 
gases  are  revolved  by  means  of  a  baffle  plate  which  throws  down  any 
solid  particles  of  carbon  and  allows  the  gas  to  pass  out.  Its  parts 
are  all  of  cast  iron  so  that  there  is  no  screen  to  burn  out,  while  the 
amount  of  back  pressure  is  said  to  be  negligible.  From  preliminary 
tests  this  promises  to  be  a  very  satisfactory  device.  Two  handfuls  of 
sawdust  were  recently  thrown  into  the  carburetor  of  a  machine 
equipped  with  this  spark  arrester.  As  far  as  could  be  determined 
none  of  it  got  through  and  the  residue  was  found  trapped  in  the 
device  when  the  cover  was  removed.  It  is  hoped  that  field  tests  will 
show  it  to  be  as  satisfactory  a  device  as  was  indicated  by  its  initial 
performance. 

HOME-MADE  SPARK  ARRESTERS 

While  in  general  a  home-made  device  is  apt  to  be  less  perfect  than 
one  built  for  the  machine  at  the  factory,  several  men  have  developed 
spark  arresters  which  have  furnished  the  required  protection.  Sec- 
ondary screens  have  generally  been  box-like  in  shape,  with  one  to 
several  layers  of  window  screen,  and  have  been  used  as  an  added 
protection  around  the  regular  spark  arrester.  When  built  with  square 
corners  and  screen  top  they  are  open  to  the  objection  that  chaff  and 
straw  may  settle  on  the  top,  or  in  a  high  wind  collect  on  the  windward 
side.  Here  it  is  apt  to  be  set  on  fire  from  the  heat  and  blow  off  into 
the  grain  when  the  direction  of  the  machine  is  changed.  If  the  outer 
screen  is  not  large  enough,  explosive  gases  often  collect  in  it  and  then 
burn  on  the  outside  of  the  screen. 

The  most  satisfactory  device  of  this  kind  is  the  screened  cylinder 
used  by  Hahn  Brothers  of  Arbuckle.  This,  as  shown  in  the  picture, 
is  a  cylindrical  frame  24  inches  in  diameter  and  24  inches  high,  built 
of  1-inch  strap  iron,  the  six  uprights  being  riveted  to  top  and  bottom 
hoops.  The  top  and  bottom  are  solid,  made  of  No.  16  galvanized  iron 
turned  up  at  the  edges  to  fit  over  the  hoops  to  which  they  are  fastened 
with  stove  bolts.  The  bottom  should  be  fitted  tightly  around  the 
exhaust  pipe  which  can  be  accomplished  by  cutting  a  hole  the  exact 
size  of  the  pipe  out  of  the  center  of  a  tin  pie  plate.  The  plate  can 
be  forced  over  the  pipe  after  the  bottom  of  the  cylinder  is  in  place. 


358 


UNIVERSITY    OP    CALIFORNIA EXPERIMENT    STATION 


The  sides  should  he  covered  with  a  double  thickness  of  window  screen 
fastened  to  the  frame  with  light  wire.  The  cylinder  is  held  rigidly  to 
the  top  of  the  cab  by  four  long  3/8-inch  bolts  passing  through  two  strap 
iron  pieces  on  the  top  and  tightened  up  by  means  of  thumb  nuts  on 
the  under  side  of  the  canopy  supports.  It  will  be  convenient  to  have 
a  small  opening  in  the  top,  closed  by  a  sliding  door  which  should  fit 


Hxj&eScretm  JparA Arrester 

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Fig.  6. — Detail  of  the  new  Best  spark  arrester,  with  double  screen  and  cast 
top  and  bottom.  Not  tested  as  yet,  but  unquestionably  much  superior  to  the  old 
conical  type. 

tightly  enough  so  as  not  to  jar  open  when  the  machine  is  running. 
This  will  allow  the  inside  of  the  cylinder  and  the  regular  spark  arrester 
inside  to  be  brushed  free  of  carbon  without  removing  the  top.  To 
insure  safety  this  cleaning  should  be  done  at  least  once  each  day. 
This  device  was  used  last  season  on  a  Holt  machine  pulling  a  33-foot 
combine.     The  old  type  arrester  was  used  inside  and  the  outfit  gave 


FIRE   PROTECTION   FOR   GRAIN    FIELDS 


359 


perfect  protection.  IT  used  on  a  tractor  with  double  exhaust  pipes 
two  cylinders  18  inches  by  18  inches  can  be  used.  The  cost  of  these 
complete  should  not  exceed  ten  dollars  each. 

The  Water  Jackt  t  Spark  Arrester  was  devised  by  Mr.  George  Ellis 
of  Willows  in  1916.     It  gave  such  good  protection  that  last  year  seven 


Fig.  7. — The  screened  cylinder  auxiliary  spark  arrester.  It  is  light  in  weight, 
cheap,  easy  to  construct  and  if  kept  clean  lias  given  excellent  protection  when 
used  outside  of  the  regular  arrester.  (A)  Strap  iron  cylindrical  frame  covered 
with  double  thickness  of  window  screen.  The  top  is  No.  16  galvanized  iron  and 
can  be  made  with  a  sliding  door  to  facilitate  cleaning.  (B)  Galvanized  iron 
bottom  through  which  the  exhaust  pipe  runs.      (C)   Regular  arrester  used  inside. 

or  eight  machines  in  Glenn  County  were  similarly  equipped  and  all 
of  the  users  seem  to  be  satisfied  that  it  gives  perfect  protection  from 
sparks.  As  indicated  in  the  diagram  it  depends  for  its  efficiency  on 
turning  the  exhaust  gases  through  a  horizontal  pipe  and  allowing  them 


360 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


to  escape  downward  into  a  tank  containing  a  little  water  in  the  bottom. 
A  hot  water  boiler,  16  inches  in  diameter,  with  the  top  cnt  out,  will 
serve  for  the  tank,  while  the-pipe  can  be  made  of  two  cast  iron  soil 
pipe  elbows  riveted  to  a  connecting  pipe  of  No.  16  galvanized  iron. 
The  entire  tank  and  pipe  can  be  constructed  of  No.  16  galvanized  iron 
by  a  good  tinsmith.  If  this  is  done  it  is  necessary  that  all  joints  be 
riveted  instead  of  soldered.  Mr.  Ellis  had  his  made  in  this  way,  the 
pipe  being  covered  with  light  asbestos  wired  on.  After  two  seasons' 
use  this  pipe  shows  scarcely  any  sign  of  wearing  out. 


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Fig.  8. — The  water  jacket  arrester  provides  great  safety  under  careless  or 
inefficient  operation  of  the  engine.  It  does  not  have  to  be  brushed  off  daily  in 
order  to  be  effective  and  the  opening  is  so  far  removed  from  the  engine  that  it  is 
practically  impossible  to  make  it  flame  when  using  an  excess  of  lubricating  oil. 


In  setting  up  the  water  jacket  the  tank  is  usually  set  on  the  running 
board  to  which  it  is  fastened  by  two  long  %-inch  rods,  each  being 
fitted  with  a  hook  at  one  end  and  a  thread  and  nut  at  the  other.  The 
upper  end  is  hooked  over  the  top  of  the  tank,  the  lower  passing 
through  the  running  board  on  the  under  side  of  which  the  nut  is 
tightened  up.  To  give  added  rigidity  a  piece  of  2-inch  plank  is  shaped 
to  fit  the  curve  of  the  tank,  clamped  to  it  by  means  of  an  iron  band 
and  bolted  to  the  radiator  platform.  The  top  of  the  tank  should  be 
well  above  the  canopy  in  order  that  the  poisonous  exhaust  gases  will 
not  blow  back  in  the  operator's  face.     If  a  short  boiler  is  used  an 


FIRE  PROTECTION  FOR  GRAIN   FIELDS 


361 


extension  of  sheet  iron  can  be  riveted  to  the  top  into  which  a  slot 
should  be  cut  on  the  side  toward  the  engine.  The  curved  exhaust  pipe 
can  rest  in  this  slot  which  will  prevent  its  jarring  loose.  Only  a  few 
inches  of  water  in  the  bottom  of  the  tank  are  necessary  though  it  is 
well  to  put  in  a  foot  or  two  in  the  morning  as  the  loss  through  exapora- 
tion  will  exhaust  from  three  to  five  gallons  a  day. 


Fig.  9. — Detail  of  Holt  engine  showing  air  clarifier  and  connections.  The 
exhaust  pipe  and  manifold  are  danger  points  as  they  become  exceedingly  hot. 
A  sheet  iron  shield  is  being  supplied  to  enclose  these.  The  old  type  spark 
arrester  shown  in  the  foreground  proved  to  be  ineffective  under  dangerous 
conditions  and  has  been  discarded  in  favor  of  the  centrifugal  type. 

The  water  jacket  arrester  is  open  to  several  serious  objections: 

(1)  It  is  bulky  and  weighs  upwards  of  250  pounds  without  the 
water. 

(2)  It  is  expensive,  costing  from  $30.00  to  $50.00,  depending  on 
local  conditions. 


362 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


(3)  It  turns  the  exhaust  gases  through  two  right  angles  which 
causes  some  back  pressure  and  consequent  heating  of  the  engine. 

(4)  If  the  carburetor  acts  slowly  or  one  cylinder  is  missing  the 
unburned  charge  of  gas  is  apt  to  explode  in  the  pipe.  This  seems  to 
be  a  rare  occurrence,  however. 

(5)  When  installed  on  a  machine  with  double  exhaust  pipes  a  pipe 
should  lead  from  each  of  them  to  the  water  tank. 

People  who  have  used  this  device  consider  that  these  disadvantages 
do  not  outweigh  the  big  advantage  of  securing  perfect  control  of  hot 
carbon  sparks. 


Fig.  10. — Detail  of  Best  engine  showing  air  clarifier  attached  to  flat  top  stove. 
The  double  exhaust  pipes  are  cooler  than  a  single  one,  but  the  flat  top  of  air 
heater  (H)  is  a  danger  point  for  the  protection  of  which  a  conical  shield  is  now 
being  supplied. 


Protection  for  exhaust  pipes  and  manifolds  has  been  provided  by 
each  of  the  companies.  This  will  be  accomplished  by  means  of  sheet- 
iron  shields  made  in  two  parts.  These  can  be  slipped  on  and  bolted 
in  a  few  minutes  and  will  completely  enclose  these  parts  of  the 
machine  giving  an  air  space  all  around  of  about  an  inch.  Use  of  these 
shields  is  particularly  advisable  in  localities  having  peaty  soils.    Dust 


FIRE   PROTECTION    FOR   GRAIN    FIELDS  )5().'{ 

from  this  soil  is  apt  to  collect  on  exhaust  pipes  before  they  become 
heated,  taking  fire  later  and  blowing  into  the  grain  while  burning. 
Owners  of  machines  can  procure  these  shields,  as  well  as  the  new 
spark  arrester,  either  from  the  local  agent  or  from  the  factory  direct. 
Static  electricity  frequently  causes  fires  in  very  dusty  or  smutty 
grain  where  some  of  the  moving  parts  of  the  separator  are  insulated 
from  grounded  parts  of  the  machine  by  oil  in  the  bearings.  The 
electric  charge  collects  on  these  parts  until  it  is  of  sufficient  intensity 
to  jump  to  a  grounded  part  of  the  machine  which  is  accompanied  by 
a  blue  spark  of  greater  or  less  intensity,  depending  on  the  charge. 
This  can  be  obviated  in  the  case  of  a  stationary  machine  by  connecting 
all  such  parts  to  a  wire  which  is  in  turn  driven  into  a  moist  spot  in 
the  ground.  This  has  not  been  an  important  cause  of  fires  in  Cali- 
fornia, but  is  very  dangerous  where  smutty  wheat  is  being  harvested. 
For  detailed  wiring  plans  and  discussion  of  this  subject,  see  (1)  and 
(3)  under  "Literature." 

OTHER  SAFETY  MEASURES 

Smoking  should  be  discouraged  at  all  times  in  the  harvest  field. 
Many  men  believe  in  prohibiting  it  entirely  and  will  immediately 
discharge  any  man  who  smokes.  If  allowed  it  should  only  be  at 
stated  times,  as  after  lunch,  when  the  machinery  is  not  running  and 
when  the  men  are  in  close  proximity  to  the  machine  where  fire 
extinguishers  are  instantly  available.  Giving  up  tobacco  except  under 
these  conditions  is  a  small  discomfort  in  order  to  insure  the  safety  of 
food  supplies  which  may  be  destroyed  by  a  fire. 

Matches  dropped  into  the  separator  have  been  the  cause  of  more 
than  one  fire  and  great  care  should  be  taken,  particularly  in  the  case 
of  stationary  outfits.  It  will  be  found  advisable  to  furnish  safety 
matches  to  all  the  men  and  prohibit  their  carrying  the  ordinary 
"parlor"  match  into  the  field.  Safety  matches  must  be  struck  on  the 
box  and  do  not  constitute  a  menace  if  dropped  carelessly.  After 
extinguishing,  always  hold  a  match  until  it  is  cold  or  break  it  in  two 
before  throwing  it  away. 

Friction,  which  causes  hot  boxes  as  a  result  of  improper  lubrication 
or  defective  alignment  of  running  parts,  is  an  inexcusable  cause  of 
fires  because  with  proper  precautions  it  can  be  eliminated.  Gravel, 
chunks  of  earth,  or  even  large  weed  stems,  sometimes  cause  fires 
because  of  friction  sparks  in  the  separator.  Care  should  be  taken 
to  exclude  all  foreign  matter  of  this  kind.  In  some  very  stony  fields 
fires  have  been  set  by  friction  sparks ;  the  result  of  wheels  or  treads 


364  UNIVERSITY    OF    CALIFORNIA — EXPERIMENT   STATION 

slipping  off  from  flinty  rocks.  Extreme  watchfulness  and  a  good  fire 
extinguisher  are  the  best  safeguards  when  working  in  a  field  of  this 
character.  '■    '|*J 

FIRE    FIGHTING    EQUIPMENT 

In  spite  of  the  best  laid  prevention  plans  some  fires  will  un- 
doubtedly start.  When  this  occurs  equipment  should  be  at  hand 
to  extinguish  them  and  every  man  in  the  threshing  crew  should  be 
drilled  beforehand  so  that  he  will  know  exactly  what  to  do  and  how 
to  do  it.  Many  disastrous  fires  have  occurred  in  the  past  because 
nothing  was  at  hand  to  fight  them  with  when  they  started. 

Fire  extinguishers  should  be  considered  an  absolutely  essential 
part  of  every  harvesting  outfit.  The  2V2-gallon  warehouse  type  acid- 
and-soda  extinguisher  is  the  most  effective  weapon  for  fighting  grain 
fires  when  used  properly.  It  needs  only  to  be  turned  bottom  side  up 
to  begin  working,  and  will  throw  a  stream  of  water  about  forty  feet. 
A  single  charge  lasts  one  minute  and  when  used  properly  will  wet 
down  from  two  to  three  hundred  feet  of  fire  in  standing  grain.  A 
box  containing  a  few  extra  charges  should  be  kept  on  the  machine. 
One  charge  consists  of  one  and  one-half  pounds  of  bicarbonate  of 
soda  (baking  soda)  and  a  four-ounce  bottle  of  sulphuric  acid.  The 
soda  should  be  thoroughly  dissolved  in  the  water  so  that  no  particles 
are  left  which  may  clog  the  hose.  The  acid  is  placed  in  a  bottle  held 
in  a  rack  in  the  top  of  the  extinguisher.  The  bottle  has  a  heavy  loose 
stopple  which  falls  out  when  the  device  is  reversed,  allowing  the  acid 
to  run  into  the  other  solution.  The  resultant  chemical  action  sup- 
plies the  pressure  for  throwing  the  stream  of  water.  Two  of  these 
extinguishers  with  a  half-dozen  extra  charges  and  a  bucket  for  dis- 
solving the  soda  will  enable  a  couple  of  men  to  extinguish  almost  any 
fire  in  its  early  stages.  A  list  of  these  extinguishers  approved  by  the 
National  Board  of  Fire  Underwriters  is  given  on  page  366.  Several 
of  these  makes  are  listed  at  about  $18.00  each,  but  are  subject  to  a 
30  per  cent  discount  in  lots  of  one  dozen,  f.  o.  b.  San  Francisco  or 
Los  Angeles. 

Chemicals  for  extra  charges  can  be  purchased  at  local  drug  stores, 
and  will  cost  from  30c  to  50c  each.  It  will  be  advisable  to  carry  the 
extra  charges  of  acid  in  bottles  which  are  the  same  as  that  in  the 
extinguishers.  This  will  obviate  the  necessity  of  pouring  the  acid 
from  one  bottle  to  another,  also  preventing  loss  of  bottles  from  crack- 
ing. When  the  extinguisher  is  used  several  times  in  quick  succession 
with  the  single  bottle,  the  chemical  action  heats  up  the  glass,  which 
is  apt  to  fly  to  pieces  when  the  cold  water  of  the  next  charge  hits  it. 


FIRE   PROTECTION   FOR   (J RAIN    FIELDS  365 

Yolo  County  Ordinance  No.  95  requires  that  every  harvesting 
outfit  shall  be  supplied  with  three  fire  extinguishers  of  approved 
design.  The  acid-and-soda  type  is  excellent  for  fires  in  grain,  but 
is  not  very  effective  in  putting  out  a  fire  in  oil,  gasoline,  or  distillate. 
For  this  the  one-quart  size  hand  extinguisher  with  double-acting 
siphon  pump  is  very  effective.  These  cost  about  $10.00  each  complete, 
while  the  liquid  for  refilling  (carbon  tetrachloride)  costs  $1.50  per 
quart  in  cans.  The  price  in  lots  of  one  dozen  extinguishers  is  sub- 
ject to  a  S3y3  per  cent  discount,  f.  o.  b.  San  Francisco.  The  carbon 
tetrachloride  liquid  changes  upon  being  heated  into  a  heavy  non- 
combustible  gas  which  smothers  the  fire. 

OTHEE  FIKE-FIGHTING  EQUIPMENT 

A  simple  but  very  efficient  piece  of  equipment  with  greater 
capacity  than  the  fire  extinguishers  mentioned  and  at  the  same  time 
more  easily  transported  into  inaccessible  places  is  the  man  pack  water 
bag  and  fire  pump,  developed  last  year  by  the  "Western  Forestry  and 
Conservation  Association.  A  water-proofed  canvas  bag  holding  from 
seven  to  eight  gallons  of  water  is  fitted  with  shoulder  straps  like  a 
regulation  pack  sack.  A  double-acting  siphon  pump  worked  by  hand 
draws  water  from  the  bottom  of  the  bag  through  a  short  piece  of 
hose.  The  pump  will  throw  a  stream  of  water  forty  feet.  This 
equipment  costs  about  $8.00  and  is  highly  recommended  by  the  fire 
wardens  of  the  Oregon  Forest  Fire  Association  who  used  it  last  year. 
These  outfits  may  be  purchased  through  the  above  association,  address 
525  Yeon  Bldg.,  Portland,  Ore. 

A  box  containing  from  six  to  ten  sacks  or  pieces  of  burlap  folded 
and  kept  moistened  is  an  excellent  thing  to  have  at  hand  on  the  tractor 
or  harvester.  A  couple  of  men  using  these  can  follow  after  one  using 
an  extinguisher  and  effectually  put  out  any  sparks  which  may  remain. 

Earth,  particularly  if  light  and  sandy  in  texture,  is  a  good 
thing  with  which  to  fight  fire.  In  order  to  use  it  one  or  two  broad 
hoes  and  the  same  number  of  sharp-nosed  shovels  should  be  kept  at 
hand.  The  hoe  can  be  used  in  digging  up  a  rough  fire  line  if  the  fire 
is  not  traveling  too  fast,  or  a  wet  sack  can  be  tie^  to  the  blade  and 
pushed  along  over  the  edge  of  the  fire.  A  rake  can  also  be  used  for 
this  purpose.  A  furrow  turned  up  with  a  plow  will  often  stop  a 
small  fire  or  make  it  safe  to  back-fire  against  a  big  one.  If  the  fire 
has  reached  a  stage  where  such  measures  are  necessary  it  will  probably 
be  beyond  the  control  of  the  threshing  crew  and  need  the  services  of 
the  community  fire-fighting  organization  to  extinguish  it.    A  back-fire 


366  UNIVERSITY    OP    CALIFORNIA — EXPERIMENT    STATION 

should  be  set  with  great  care  and  only  under  the  direction  of  a  fire 
warden  or  the  local  fire  boss.  If  started  at  the  wrong  place  or  time 
it  may  become  more  dangerous  than  the  fire  it  was  set  to  control. 

CARE    OF    MACHINERY 

In  closing  it  may  be  said  that  the  easiest  way  to  avoid  a  fire  is 
to  prevent  it.  One  of  the  simplest  preventive  measures  is  to  keep 
the  machinery  in  the  best  of  repair  at  all  times.  Before  commencing 
with  the  harvest  go  over  the  tractor  and  combine  carefully  to  find  and 
repair  the  minutest  break  or  defect.  See  that  all  parts  are  in  proper 
alignment  and  that  worn  bearings  or  gears  are  replaced.  Pay  par- 
ticular attention  to  lubrication  of  the  machines,  going  at  it  sys- 
tematically with  the  idea  that  no  spot  will  be  overlooked.  Use  enough 
oil  in  the  proper  place,  but  do  not  allow  excess  to  run  over  the 
machinery  where  it  will  collect  grit  and  dust,  and  do  not  fill  crank 
case  too  full.  Be  sure  that  the  carburetor  is  adjusted  to  insure  perfect 
combustion,  the  ideal  being  to  give  the  motor  as  much  air  and  as 
little  fuel  as  it  will  handle  to  produce  the  recpiired  power.  Black  or 
brown  smoke  from  exhaust  always  indicates  too  rich  a  mixture.  The 
exhaust  gases  should  be  colorless.  Satisfy  yourself  bj'  thorough  tests 
at  night  when  you  can  see  sparks,  that  your  spark-arresting  device  is 
giving  100  per  cent  protection  and  inspect  it  often  enough  to  be  sure 
that  it  maintains  this  standard.  Systematic  precautions  beforehand 
may  save  you  several  hours'  or  days'  loss  of  time  during  the  rush  of 
the  harvest  season  when  every  minute  counts.  Follow  the  measures 
outlined  in  "The  Six  Rules,"  and  adopt  any  others  which  may  seem 
advisable  in  your  particular  case. 

SIX    RULES   FOR   PREVENTION    OF   FIRE    IN   GRAIN    FIELDS 

RULE  ONE — Keep  your  machinery  in  repair,  well  lubricated  and  provided  with 
an  air  clarifier  and  a  good  spark  arrester.  Hot  boxes  and  hot  carbon  cause 
30  per  cent  of  grain  fires. 

RULE  TWO — Always  have  at  hand  on  the  harvester  at  least  two  good  chemical 
■fire  extinguishers.     They  keep  little  fires  from  ' '  growing  up. ' ' 

RULE  THREE — Don't  smoke  in  the  fields.  Tobacco  may  be  satisfying,  but 
it's  "hot." 

RULE  FOUR — Break  up  big  fields  by  cutting  hay  strips  at  intervals  while  grain 
is  green.     These  give  you  a  chance  to  fight  and  confine  fire  to  a  small  area. 

RULE  FIVE — Ploiv  several  furrows  around  your  grain  field  as  a  fire  break.  Your 
neighbor  may  not  be  as  careful  as  you  are. 

RULE  SIX — Help  organise  your  community  and  install  fire  fighting  equipment  at 
convenient  points.     Get  ready  now.     After  a  fire  starts  it's  too  late. 


FIRE  PROTECTION  FOR  GRAIN   FIELDS  367 


FIRE    EXTINGUISHERS 

(List  of  companies  manufacturing  extinguishers  which  comply  with  requirements 
of  the  National  Board  of  Fire  Underwriters) 

Acid   and   Soda — 2%-Gallon — Loose    Stopple    Type 

American-La  France  Fire  Engine  Co.,  Elmira,  N.  Y. 

Badger  Fire  Extinguisher  Co.,  Boston,  Mass. 

Bentley  Mfg.  Co.,  The,  E.  A.,  St.  Louis,  Mo. 

Booth-Coulter  Cooper  and  Brass  Co.,  The,  Toronto,  Out. 

Boyd  and  Bro.,  Jas.,  Philadelphia,  Pa. 

Buffalo  Chemical  Fire  Extinguisher  Co.,  The,  Buffalo,  N.  Y. 

Childs  Co.,  O.  J.,  Utica,  N.  Y. 

Diener  Mfg.  Co.,  Geo.  W.,  Chicago,  111. 

Garth  Co.,  The,  Montreal,  P.  Q. 

Harker  Mfg.  Co.,  Cincinnati,  O. 

Knight  and  Thomas,  Inc.,  Boston,  Mass. 

McMorran  Co.,  Edward  E.,  Chicago,  111. 

Miller  Chemical  Engine  Co.,  Chicago,  111. 

Missouri  Lamp  and  Mfg.  Co.,  St.  Louis,  Mo. 

Northern  Fire  Apparatus  Co.,  Minneapolis,  Minn. 

Pittsburg  Lamp,  Brass  and  Glass  Co.,  Pittsburgh,  Pa. 

Pyrene  Mfg.  Co.,  New  York,  N.  Y. 

Eowe  and  Son,  New  York,  N.  Y. 

Racine  Iron  and  Wire  Works,  Racine,  Wis. 

Standard  Extinguisher  Co.,  The,  So.  Boston,  Mass. 

Stempel  Fire  Extinguisher  Mfg.  Co.,  The,  St.  Louis,  Mo. 

Victor  Fire  Extinguisher  Co.,  Toronto,  Ont. 

Western  Inspection  Co.,  Buffalo,"  N.  Y. 


Hand  Extinguishers — 1-Quart — Pump  Type 

Electrene  Co.,  New  York,  N.  Y.     "Fire  Gun." 

Fyr-Fyter  Co.,  The,  Dayton,  Ohio.    Factory,  Chicago,  111.     ' '  Fyr-Fyter. " 

Johns-Manville  Co.,  H.  W.,  New  York,  N.  Y.     "J-M." 

Justrite  Mfg.   Co.,  Chicago,  111.     "Justrite." 

Pyrene  Mfg.  Co.,  New  York,  N.  Y.     "Pyrene." 

The  Board  of  Fire  Underwriters  of  the  Pacific  give  the  following: 
as  official  San  Francisco  agents  for  approved  fire  extinguishers : 

American-La  France  Fire  Engine   Co.,   151   New  Montgomery   St. 

Badger  Fire  Extinguisher  Co.,  507  Montgomery  St. 

Boyd  Bros.  Co.,  c/o  Paul  Brant,  67  Main  St. 

Childs  and  Co.,  c/o  Ralph  Pugh  Co.,  532  Howard  St. 

Johns-Manville  Co.,  H.  W.,  Second  and  Howard  Sts. 

Knight  &  Thomas,  c/o  E.  T.  Bond,  311  California  St. 


368  UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 

Missouri  Lamp  and  Mfg.  Co.,  c/o  Goodyear  Kubber  Co.,  587  Market  St. 

Northern  Fire  Apparatus  Co.,  c/o  P.  Brant,  67  Main  St. 

Pittsburgh  Lamp,  Brass  and  Glass  Co.,  c/o  A.  A.  Otte,  618  Mission  St. 

Pyrene  Mfg.  Co.,  76  First  St. 

Standard  Extinguisher  Co.,  c/o  Gorham  Fire  Ex.  Co.,  127  Mission  St. 

Stempel  Fire  Extinguisher  Mfg.  Co.,  c/o  P.  Brant,  67  Main  St. 


LITERATURE 

1.  Fire  Prevention  and  Fire  Fighting  on  the  Farm.     H.  E.   Tolley  and  A.   P. 

Yerkes.    Farmers'  Bulletin  904,  U.  S.  Dept.  of  Agriculture,  January,  1918. 

2.  Suggestions  for  Fire  Prevention  and  Protection  as  Applied  to  Grain  Separators. 

Washington  Surveying  and  Rating  Bureau,  Seattle,  Wash.,  July,  1917. 

3.  Dust  Explosions  and  Fires  in  Grain  Separators  in  the  Pacific  Northwest.    U.  S. 

Dept.  of  Agriculture  Bulletin  no.  379. 

4.  Care  and  Repair  of  Farm  Implements.     E.  B.  McCormick  and  L.   L.  Beebe. 

Farmers'  Bulletin  947. 
Numbers  1,  3  and  4  may  be  obtained  free  of  charge  from  the  Editor  and 
Chief   of  the  Division  of   Publications,  Washington,  D.   C.     Number   2   may   be 
secured  from   the   bureau   above   mentioned.     Address   P.   O.    Box   1818,   Seattle, 
Wash. 


